You can have the antibodies and still get sickDocument Transcript
March 28, 1997 / Vol. 46 / No. RR-7
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Centers for Disease Control
and Prevention (CDC)
Atlanta, Georgia 30333
Use of Acellular Pertussis Vaccines
Among Infants and Young Children
Recommendations of the Advisory Committee on
Immunization Practices (ACIP)
Copies can be purchased from Superintendent of Documents, U.S. Government
Printing Office, Washington, DC 20402-9325. Telephone: (202) 783-3238.
Use of trade names and commercial sources is for identification only and does not
imply endorsement by the Public Health Service or the U.S. Department of Health
and Human Services.
The MMWR series of publications is published by the Epidemiology Program Office,
Centers for Disease Control and Prevention (CDC), Public Health Service, U.S. Depart-
ment of Health and Human Services, Atlanta, GA 30333.
Centers for Disease Control and Prevention.......................... David Satcher, M.D., Ph.D.
The material in this report was prepared for publication by:
National Immunization Program ...........................................Walter A. Orenstein, M.D.
Epidemiology and Surveillance Division ............................ Stephen C. Hadler, M.D.
The production of this report as an MMWR serial publication was coordinated in:
Epidemiology Program Office.................................... Stephen B. Thacker, M.D., M.Sc.
Richard A. Goodman, M.D., M.P.H.
Editor, MMWR Series
Office of Scientific Communications (proposed)
Recommendations and Reports................................... Suzanne M. Hewitt, M.P.A.
Robert S. Black, M.P.H.
Morie M. Higgins
Peter M. Jenkins
Visual Information Specialists
Centers for Disease Control and Prevention. Pertussis vaccination: use of acellular
pertussis vaccines among infants and young children — recommendations of the
Advisory Committee on Immunization Practices (ACIP). MMWR 1997;46(No.
RR-7):[inclusive page numbers].
Whole-Cell Pertussis Vaccines.......................................................................2
Trends in Pertussis Disease in the United States .......................................2
Acellular Pertussis Vaccines ..........................................................................3
Studies of the Efficacy of DTaP Vaccines in Infants....................................4
Interpretation of Immunogenicity Data........................................................4
Simultaneous Administration .......................................................................8
Simultaneous Administration .....................................................................11
Simultaneous Administration .....................................................................13
Simultaneous Administration .....................................................................16
Recommended Childhood Vaccination Schedule.....................................17
Licensed Products .........................................................................................18
Dosage and Administration .........................................................................18
Interchangeable Use of Acellular Pertussis Vaccines ..............................19
Simultaneous Administration of Vaccines.................................................19
Reporting Of Adverse Events After Vaccination ..............................................22
Vaccine Injury Compensation............................................................................22
Vol. 46 / No. RR-7 MMWR i
Advisory Committee on Immunization Practices
Membership List, June 1996
Jeffrey P. Davis, M.D.
Chief Medical Officer
Department of Health and
State of Wisconsin
ACTING EXECUTIVE SECRETARY
Dixie E. Snider, M.D., M.P.H.
Associate Director for Science
Centers for Disease Control
Barbara Ann DeBuono, M.D.
Rhode Island Department of Health
Mary P. Glode, M.D.
The Children’s Hospital
Marie R. Griffin, M.D., M.P.H.
Vanderbilt University Medical Center
Fernando A. Guerra, M.D.
San Antonio Metro Health District
San Antonio, TX
John F. Modlin, M.D.
Dartmouth Medical School
Stephen C. Schoenbaum, M.D.
Harvard Community Health Plan of
Jessie L. Sherrod, M.D., M.P.H.
Martin Luther King, Jr.
Los Angeles, CA
Fred E. Thompson, Jr., M.D.
Mississippi State Department of Health
Joel Ira Ward, M.D.
Harbor-UCLA Medical Center
EX OFFICIO MEMBERS
Robert F. Breiman, M.D.
Centers for Disease Control
Geoffrey Evans, M.D.
Health Resources and Services
Carolyn Hardegree, M.D.
Food and Drug Administration
John La Montagne, Ph.D.
National Institutes of Health
Kristen Lee Nichol, M.D., M.P.H.
VA Medical Center
Relford E. Patterson
U.S. Department of Defense
Jerry Zelinger, M.D.
Health Care Financing Administration
ii MMWR March 28, 1997
Advisory Committee on Immunization Practices
Membership List, June 1996 — Continued
American Academy of Family
Richard Zimmerman, M.D.
American Academy of Pediatrics
Georges Peter, M.D.
Neal A. Halsey, M.D.
American College of Obstetricians
Stanley A. Gall, M.D.
American College of Physicians
Pierce Gardner, M.D.
American Hospital Association
William Schaffner, M.D.
Association of Teachers of
Richard D. Clover, M.D.
Canadian National Advisory Committee
David Scheifele, M.D.
Vancouver, British Columbia
Hospital Infections Control
Practices Advisory Committee
David W. Fleming, M.D.
Infectious Diseases Society of America
William P. Glezen, M.D.
Pharmaceutical Research and
Manufacturers of America
David J. Williams
Vol. 46 / No. RR-7 MMWR iii
The following CDC staff members prepared this report:
Dalya Guris, M.D., M.P.H.
Peter M. Strebel, M.B.Ch.B., M.P.H.
Hamid Jafari, M.B.B.S
Melinda Wharton, M.D., M.P.H.
Stephen C. Hadler, M.D.
Division of Epidemiology and Surveillance
National Immunization Program
iv MMWR March 28, 1997
Use of Acellular Pertussis Vaccines Among Infants
and Young Children
Recommendations of the Advisory Committee on
Immunization Practices (ACIP)
Concerns about the safety of whole-cell pertussis vaccines prompted devel-
opment of acellular vaccines that are less likely to provoke adverse events
because they contain purified antigenic components of Bordetella pertussis.
Two diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccines—
* and Tripedia®†
—have been licensed for several years, but (until
recently) only for administration of the fourth and fifth doses in the series to
children aged 15 months–6 years who previously had received three or more
doses of diphtheria and tetanus toxoids and whole-cell pertussis (DTP) vaccine.
Published reports indicate that, when administered to infants aged 2, 4, and 6
months, acellular pertussis vaccines are effective in preventing pertussis dis-
ease and associated with fewer local, systemic, and certain more serious
adverse events than whole-cell pertussis vaccines. On the basis of these data,
the Food and Drug Administration (FDA) has licensed three DTaP vaccines for
use among children aged 6 weeks–6 years. Tripedia®
is now licensed for the
initial four doses, and ACEL-IMUNE®
for all five doses of the diphtheria, tetanus
and pertussis vaccination series. A third DTaP vaccine (Infanrix™ )§
in January 1997 for the initial four doses of the series. Tripedia®
and Infanrix™ are now recommended for routine vaccination of infants and
young children, although whole-cell pertussis vaccines remain acceptable alter-
, and Infanrix™ are recommended for all
remaining doses in the schedule for children who have started the vaccination
series with one, two, three, or four doses of whole-cell pertussis vaccines. In
September 1996, FDA licensed the use of TriHIBit™ (ActHIB®
for the fourth dose in the series of vaccinations against diphtheria,
tetanus, pertussis, and Haemophilus influenzae type b disease.
*Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed, ACEL-IMUNE®,
prepared by Lederle Laboratories and distributed by Wyeth-Lederle Vaccines and Pediatrics
(Pearl River, New York) was licensed on December 30, 1996 for use in infants. The acellular
pertussis vaccine component is produced by Takeda Chemical Industries, Ltd. (Osaka, Japan),
and is combined with diphtheria and tetanus toxoids manufactured by Lederle Laboratories.
†Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed, prepared and dis-
tributed as Tripedia® by Connaught Laboratories, Inc. (Swiftwater, Pennsylvania), was licensed
July 31, 1996 for use in infants. The acellular pertussis vaccine component is produced by
BIKEN/Tanabe Corporation (Osaka, Japan), and is combined with diphtheria and tetanus
toxoids manufactured by Connaught Laboratories, Inc.
§Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed, prepared and dis-
tributed as Infanrix™ was licensed January 29, 1997. The diphtheria and tetanus toxoids are
produced by Chiron Behring GmbH & Co. (Marburg, Germany). The acellular pertussis com-
ponent is manufactured by SmithKline Beecham Biologicals S. A. (Rixenart, Belgium).
¶Haemophilus b Conjugate Vaccine (Tetanus Toxoid Conjugate) is manufactured by Pasteur
Mérieux Sérums & Vaccins S.A. ActHIB® is identical to Haemophilus b Conjugate Vaccine
(Tetanus Toxoid Conjugate)—OmniHIB® (distributed by SmithKline Beecham Pharmaceuticals)
and is manufactured by Pasteur Mérieux Sérums & Vaccins S.A.
Vol. 46 / No. RR-7 MMWR 1
This statement a) provides general information regarding whole-cell pertus-
sis vaccines currently licensed in the United States; b) summarizes results of
recent studies of the immunogenicity, efficacy, and safety of acellular pertussis
vaccines administered to infants and young children; c) presents recommenda-
tions for the use of Tripedia®
, TriHIBit™ , ACEL-IMUNE®
, and Infanrix™ vaccines;
and d) supplements previous recommendations on pertussis vaccination.
Whole-Cell Pertussis Vaccines
Four diphtheria and tetanus toxoids combined with whole-cell pertussis (DTP) vac-
cines are presently licensed for use in the United States.* Vaccines of this type,
prepared from suspensions of inactivated Bordetella pertussis bacterial cells, have
been licensed for routine vaccination of infants since the mid-1940s. Based on control-
led efficacy trials conducted in the 1940s and on subsequent observational efficacy
studies, a primary series comprising four doses of whole-cell DTP vaccine is consid-
ered 70%–90% effective in preventing serious pertussis disease (1–4 ).
Whole-cell DTP vaccines are commonly associated with several local adverse
events (e.g., erythema, swelling, and pain at the injection site), fever, and other mild
systemic events (e.g., drowsiness, fretfulness, and anorexia) (5,6 ). More severe sys-
temic events (e.g., convulsions [with or without fever] and hypotonic hyporesponsive
episodes) occur less frequently (ratio of one case to 1,750 doses administered) among
children who receive whole-cell DTP vaccine (5 ). Acute encephalopathy occurs even
more rarely (ratio of 0–10.5 cases to one million doses administered) (7 ). Experts dis-
agree on whether whole-cell pertussis vaccine causes lasting brain damage, but agree
that if the vaccine causes such damage it does so only rarely (7 ). Concerns about
safety prompted the development of more purified (acellular) pertussis vaccines that
are associated with a lower frequency of adverse events and are effective in prevent-
ing pertussis disease.
Trends in Pertussis Disease in the United States
In the United States, the highest recorded annual incidence of pertussis occurred in
1934 when >260,000 cases were reported. The incidence of reported pertussis disease
declined substantially as use of whole-cell DTP vaccines became widespread. By 1970,
the reported incidence had declined >99%; the fewest cases (1,010) were reported in
1976. However, since the early 1980s reported pertussis incidence has increased
steadily. Cyclical peaks in incidence occurred in 1983, 1986, 1990, and in 1993 when
6,586 cases were reported—more than in any year since 1976 (8 ). The number of re-
ported cases has increased in all age groups, but the increase is greatest among
persons aged ≥5 years (9 ). Nevertheless, infants and young children continue to have
the highest risk for pertussis and its complications (4,8,10 ).
*Whole-cell DTP vaccines are manufactured by Connaught Laboratories Inc., Lederle Laborato-
ries, Massachusetts Public Health Biologic Laboratories, and Michigan Biologic Products
Institute; those produced by Connaught Laboratories and Lederle Laboratories are distributed
2 MMWR March 28, 1997
The increase in reported pertussis cases has occurred despite pertussis vaccina-
tion coverage levels that are higher than at any time in the past. The proportion of
children aged 19–35 months who had received three or more doses of whole-cell DTP
or diphtheria and tetanus toxoids vaccine (DT) reached 93% in 1994 (11 ). (Of those
vaccinated, <2% are estimated to have received DT [CDC, unpublished data].) Possible
explanations of this increase in disease include a) decreased vaccine efficacy, b) wan-
ing immunity among adolescents and adults vaccinated during childhood, c)
increased diagnosis and reporting of pertussis because of greater awareness among
physicians about the disease, and d) enhanced surveillance and more complete re-
porting in some states (12,13 ).
Recent randomized controlled trials in Sweden and in Italy with one of the whole-
cell DTP vaccines presently licensed in the United States (manufactured by Connaught
Laboratories, Inc.) yielded estimates of low clinical efficacy—60% in the 6 months im-
mediately following administration of the third dose. Estimates of vaccine efficacy for
the total followup period were even lower—48% in Sweden and 36% in Italy (14,15 ).
These estimates were substantially lower than expected on the basis of estimates ob-
tained from observational studies in the United States. One possible explanation for
the disparity is the number of doses administered—three in the trials in Sweden and
Italy versus five in the United States (doses at ages 2, 4, 6, and 12–18 months and 4–6
years). A recent study in Germany with another whole-cell DTP vaccine currently in
use in the United States (distributed by Wyeth-Lederle Vaccines and Pediatrics) dem-
onstrated 83% protective efficacy after the third dose and before administration of the
fourth dose and 94% efficacy after four doses (Wyeth-Lederle Vaccines and Pediatrics,
ACEL-IMUNE® package insert). The effectiveness of the current pertussis vaccination
program in the United States, which has relied on four different whole-cell DTP vac-
cines for primary vaccination, remains high (3,4 ).
Acellular Pertussis Vaccines
Acellular pertussis vaccines contain inactivated pertussis toxin (PT) and may con-
tain one or more other bacterial components (e.g., filamentous hemagglutinin [FHA],
a 69-kilodalton outer-membrane protein—pertactin [Pn], and fimbriae [Fim] types 2
and 3). PT is detoxified either by treatment with a chemical (e.g., hydrogen peroxide,
formalin and/or glutaraldehyde) or by using molecular genetic techniques. Acellular
pertussis vaccines contain substantially less endotoxin than whole-cell pertussis
Since 1991, two acellular pertussis vaccines (Tripedia® and ACEL-IMUNE®) have
been licensed for use in the United States. Until recently, both vaccines were licensed
for use only as the fourth and fifth doses of the diphtheria, tetanus, and pertussis
vaccination series among children aged 15 months–6 years who had received three
primary doses of whole-cell DTP (16,17 ). This licensure was based on findings of stud-
ies conducted in Sweden and Japan. These studies did not evaluate the efficacy of
acellular pertussis vaccines administered to infants on a schedule similar to the one
used in the United States and did not directly compare the efficacy of DTaP vaccines
with that of whole-cell DTP vaccines (18–22 ).
Vol. 46 / No. RR-7 MMWR 3
Studies of the Efficacy of DTaP Vaccines in Infants
Since 1991, seven studies conducted in Europe and Africa have evaluated the effi-
cacy of eight DTaP vaccines administered to infants. The vaccines, produced by
different manufacturers, contained a varying number and quantity of antigens. The
derivation and formulation of the individual antigens also varied among vaccines
(Table 1). Four doses of vaccine were administered in one study (Wyeth-Lederle
Vaccines and Pediatrics, ACEL-IMUNE® package insert); the other six studies involved
three doses (14,15,23–25 ). These studies also differed in other ways (Table 2):
• Design. Three studies were randomized placebo-controlled clinical trials; such
studies usually provide the most accurate measure of a treatment effect and are
less subject to biases than observational studies.
• Case definition. Estimates of vaccine efficacy tend to be higher when the case
definition excludes mild clinical cases.
• Laboratory method used to confirm the diagnosis of pertussis.
Because of these differences, comparisons among studies should be made with
caution. Within individual studies, however, the efficacy of acellular pertussis vaccines
can be compared directly with that of whole-cell DTP.
The efficacy of three doses of acellular pertussis vaccines in preventing moderate
to severe pertussis disease was within the range expected for most whole-cell DTP
vaccines. Point estimates of efficacy ranged from 59% to 89%. Mild local and systemic
adverse events occurred less frequently among infants vaccinated with acellular
pertussis vaccines for the first three or four doses than among those vaccinated with
whole-cell DTP. More serious adverse events (e.g., fever ≥105 F [≥40.5 C], persistent
crying of ≥3 hours duration, hypotonic hyporesponsive episodes, and seizures) gener-
ally occurred less frequently among infants who received acellular pertussis vaccines
than among those vaccinated with whole-cell DTP. The number of subjects included in
these studies was insufficient to estimate the risk for rare severe reactions (i.e.,
encephalopathy or anaphylactic shock). Surveillance for these rare adverse events will
be needed as acellular pertussis vaccines are used more widely.
Interpretation of Immunogenicity Data
The findings of efficacy studies have not demonstrated a direct correlation between
antibody responses and protection against pertussis disease. However, antibody
studies are useful to compare immune responses elicited by a single vaccine under
different conditions or in different studies. Thus, efficacy studies are required to meas-
ure clinical protection conferred by each pertussis vaccine.
On July 31, 1996, the Food and Drug Administration (FDA) licensed Tripedia® for
use as the initial four doses of the recommended diphtheria, tetanus, and pertussis
vaccination series among children aged 6 weeks–6 years. The acellular pertussis
vaccine components are purified from B. pertussis by salt precipitation, ultracentri-
fugation, and ultrafiltration. After purification, fractions containing PT and FHA are
4 MMWR March 28, 1997
TABLE 1. Vaccines containing acellular pertussis antigens combined with diphtheria and tetanus toxoids (DTaP) tested in
recent studies of efficacy among infants, by manufacturer and characteristics*
DTaP vaccines Abbreviation
NAV-1 40.0 0.50 Thimerosal 25.0 7.0 Chemical
CB-2 23.4 23.4 0.17 Thimerosal 6.7 5.0 Chemical
Pasteur Mérieux PM-2 25.0 25.0 0.50 Thimerosal 15.0 5.0 Chemical
SKB-2 25.0 25.0 0.50 Phenoxyethanol 17.0 10.0 Chemical
Biocine BSc-3P 5.0 2.5 2.5 0.35 Thimerosal 25.0 10.0 Genetic¶
SKB-3P 25.0 25.0 8.0 0.625 Phenoxyethanol 25.0 10.0 Chemical
CLL-4F2 10.0 5.0 3.0 5.0** 0.33 Phenoxyethanol 15.0 5.0 Chemical
LPT-4F1 3.2 34.4 1.6 0.8††
0.23 Thimerosal 9.0 5.0 Chemical
*Adapted from Edwards KM, Meade BD, Decker MD, et al. Comparison of 13 acellular pertussis vaccines: overview and serologic response. Pediatrics
†PT=inactivated pertussis toxin; FHA=filamentous hemagglutinin; Pn=pertactin; Fim=fimbriae.
§Measured in limit of flocculation units (Lf) per dose.
**Fim 2 and 3.
TABLE 2. Absolute efficacy of DTaP and whole-cell DTP* vaccines when administered to infants: results from seven
Site of study
Vaccine composition† Age at
(mos) Case definition
% (95% CI)
PT FHA Pn Fim DTaP DTP
Randomized controlled studies
CLL-4F2 + + + + 2, 4, 6 ≥21 days of paroxysmal cough§ 85 (81–89) 48 (37–58)¶
SKB-2 + + 2, 4, 6 ≥21 days of paroxysmal cough§
59 (51–66) 48 (37–58)¶
Italy (15) BSc-3P + + + 2, 4, 6 ≥21 days of paroxysmal cough§
84 (76–90) 36 (14–52)¶
+ + + 2, 4, 6 ≥21 days of paroxysmal cough§
84 (76–89) 36 (14–52)¶
NAV-1 + 3, 5, 12 ≥21 days of paroxysmal cough§
71 (63–78) Not studied
+ + + + 3, 5, 7, 17 ≥21 days cough and paroxysms or
whoop or vomiting and
confirmation by culture or
serology or link to culture-positive
+ + + 3, 4, 5 ≥21 days of paroxysmal cough§
89 (77–95) 98 (83–100)***
PM-2 + + 2, 4, 6 ≥21 days of paroxysmal cough§
85 (66–93) 96 (86–99)***
(Manufacturer data), (25)
CB-2 (Tripedia®) + + 3, 5, 7 ≥21 days any cough and
confirmation by culture or link to
culture; positive household contact
80 (59–90) 95 (81–99)***†††
Type of study
*Diptheria and tetanus toxoids and acellular pertussis vaccine (DTaP); diptheria and tetanus toxoids and whole-cell pertussis vaccine (DTP).
PT=pertussis toxin; FHA=filamentous hemagglutinin; Pn=pertactin; Fim=fimbriae; + indicates that vaccine contains antigen.
With culture or serologic confirmation. In Stockholm and Göteborg, cases linked to a culture-confirmed household contact were also considered
confirmed; in Senegal, cases identified as positive by polymerase chain reaction (PCR) and linked to a culture-confirmed case were also considered
DTP distributed by Connaught Laboratories, Inc. and licensed for use in the United States.
**LPT-4F1 was tested in a prospective cohort study, SKB-3P and PM-2 in household contact studies, and CB-2 in a case-control study.
In Erlangen and Senegal, children were randomly administered DTaP or whole-cell DTP; however, recruitment of DT recipients was not randomized.
Efficacy after three doses; whole-cell DTP distributed by Wyeth-Lederle Vaccines and Pediatrics and licensed for use in the United States.
Efficacy after four doses; whole-cell DTP distributed by Wyeth-Lederle Vaccines and Pediatrics and licensed for use in the United States.
***Whole-cell DTP used in six areas and Munich studies in Germany was manufactured by Behringwerke A.G.; whole-cell DTP used in Senegal was
manufactured by Pasteur Mérieux.
DTaP and whole-cell DTP vaccine efficacy estimates are not directly comparable because of differences in recruitment of children in the study.
combined to obtain a 1:1 ratio and are treated with formaldehyde to inactivate PT.
Each dose of Tripedia® contains approximately 23.4 µg protein of inactivated PT
(toxoid) and 23.4 µg protein of FHA, as well as 6.7 limit of flocculation units (Lf) of
diphtheria toxoid and 5.0 Lf of tetanus toxoid. The combined components are
adsorbed using aluminum potassium sulfate and preserved with 1:10,000 thimerosal
The Multicenter Acellular Pertussis Trial, an immunogenicity and safety study con-
ducted in six centers in the United States and sponsored by the National Institutes of
Health (NIH), compared antibody responses of infants vaccinated at ages 2, 4, and
6 months with whole-cell DTP or with one of 13 different acellular pertussis vaccines,
including Tripedia®. Antibody to pertussis antigens was measured in serum samples
taken before administration of the first dose and 1 month after administration of the
third dose of Tripedia®; 99% and 86% of children had fourfold or greater increases in
titers of antibody to PT and FHA, respectively. More than 90% of children administered
Tripedia® developed diphtheria and tetanus antibody levels indicative of immunity to
these diseases (i.e., >0.1 antitoxin units [u] per mL and >0.01 u/mL, respectively), as
did ≥90% of those administered whole-cell DTP (26 ). The immunogenicity of Tripedia®
when administered as a fourth dose to children aged 12–14 months has not been
Two studies conducted in Sweden and Germany provide data concerning the clini-
cal efficacy of Tripedia®. During 1985–1987, a randomized, placebo-controlled clinical
trial in Sweden examined the efficacy of two doses of two acellular pertussis vaccines.
The acellular pertussis component of one vaccine was comparable to the acellular
pertussis component of Tripedia® (17,18 ). The first dose was administered at age
5–11 months, the second dose 8–12 weeks later. For culture-confirmed disease with
cough of any duration, the vaccine’s efficacy after two doses was 69% (95% confi-
dence interval [CI]=47%–82%) (18 ). Using a more stringent case definition (i.e., ≥21
days paroxysmal cough and confirmation by culture) resulted in an efficacy estimate
of 81% (95% CI=61%–90%) (27 ). A non-blinded follow-up study conducted during the
42-month period following the clinical trial yielded similar results (28 ).
A case-control study in Germany evaluated the efficacy of three doses of Tripedia®
administered to children aged approximately 3, 5, and 7 months (Connaught Labora-
tories, Inc.,Tripedia® package insert). Comparison groups received whole-cell DTP
(manufactured by Behringwerke, A.G.), DT, or no vaccine. A case of pertussis was
defined as an illness with cough of ≥21 days duration and confirmation by positive
culture for B. pertussis or household contact with a culture-proven case. The esti-
mated clinical efficacy of three doses of Tripedia® compared with DT was 80% (95%
CI=59%–90%). For infants who received three doses of whole-cell DTP, the vaccine
efficacy estimate was 95% (95% CI=81%–99%) (25 ). However, the two efficacy esti-
mates are not directly comparable because of differences in the way infants were
enrolled in the two groups.
Vol. 46 / No. RR-7 MMWR 7
The safety of Tripedia® was assessed in studies conducted in the United States
and Germany. Local reactions (e.g., erythema, swelling, or pain), fever, and other com-
mon systemic symptoms (e.g., anorexia, vomiting, drowsiness, or fussiness) occurred
less frequently among infants administered Tripedia® than among those who received
whole-cell DTP (Connaught Laboratories, Inc., Tripedia® package insert). In the Mul-
ticenter Acellular Pertussis Trial, local and common systemic events occurred less
frequently among Tripedia® recipients than among recipients of whole-cell DTP (Table
3) (29 ). Among recipients of 41,615 doses of Tripedia® in the trial in Germany, few
moderate to severe adverse events occurred within 7 days after vaccination (Con-
naught Laboratories, Inc., Tripedia® package insert). The following events and rates of
occurrence (per 1,000 doses administered) were reported: persistent crying for
≥3 hours, 0.12; febrile seizures, 0.05; afebrile seizures, 0.02; and hypotonic hypore-
sponsive episodes, 0.05. Rates of invasive bacterial infections, hospitalizations,
and deaths among infants vaccinated with Tripedia® were similar to those observed
among recipients of DT. None of the deaths or invasive bacterial infections was
In a study conducted in the United States, children aged 15–20 months who had
received Tripedia® (n=109) or whole-cell DTP (n=30) for the first three doses were
administered Tripedia® as the fourth dose (30 ). Although the differences were not
statistically significant, the percentages of children who had local adverse events (e.g.,
erythema, swelling, or pain) or certain systemic adverse events (i.e., temperature
>101 F [>38.3 C] or irritability) within 72 hours after administration of the fourth dose
was higher among children who had received Tripedia® for the first three doses. How-
ever, the frequency of adverse events was lower than that observed in previous
studies in which a fourth dose of whole-cell DTP followed three previous doses of
Limited data are available to evaluate the safety of Tripedia® when administered as
a fifth dose to children aged 4–6 years who have received four previous doses of
Tripedia®. The frequency of local and mild systemic reactions after the last of five
doses was no greater among children administered Tripedia® (n=18) than among chil-
dren in the same study who were administered five doses of whole-cell DTP (n=10)
(M.E. Pichichero, unpublished data). More data concerning the safety of Tripedia® in
such circumstances are being collected and will be available before infants who
receive Tripedia® for the first four doses require a fifth dose at age 4–6 years. Data are
insufficient to assess the safety of Tripedia® administered to persons aged ≥7 years.
Data concerning the immunogenicity of Tripedia® administered simultaneously
with other childhood vaccines are limited. In a clinical study, infants received
Tripedia®, Haemophilus influenzae type b (Hib) conjugate vaccine (tetanus toxoid
conjugate) (ActHIB®), oral poliovirus vaccine (OPV), and hepatitis B vaccine simultane-
ously (Connaught Laboratories, Inc., Tripedia® package insert). In one of the study
groups, infants were administered Tripedia®, ActHIB®, and OPV at ages 2, 4, and
6 months, and hepatitis B vaccine at ages 2 and 4 months. After three doses, all of the
69 children who received ActHIB® simultaneously with Tripedia® vaccine had serum
8 MMWR March 28, 1997
TABLE 3. Percentage of infants reported to have had the indicated reaction by the third evening after any dose of pertussis
vaccine administered at ages 2, 4, and 6 months (Multicenter Acellular Pertussis Trial)*
Vaccine N Erythema Swelling Pain†
(>38.3C) Anorexia Vomiting Drowsiness Fussiness¶
Tripedia® 135 32.6** 20.0** 9.6** 5.2** 22.2** 7.4 41.5** 19.3**
ACEL-IMUNE® 217 26.3** 15.6** 3.7** 3.2** 24.9 13.4 40.6** 14.3**
InfanrixTM 120 39.2** 30.0** 10.8** 3.3** 19.2** 12.5 46.7** 15.0**
DTP†† 371 72.7 60.9 40.2 15.9 35.0 13.7 62.0 41.5
*Source: Decker MD, Edwards KM, Steinhoff MC, et al. Comparison of 13 acellular pertussis vaccines: adverse reactions. Pediatrics
† Moderate or severe: cried or protested to touch or when leg moved.
§ Rectal temperatures.
¶ Moderate or severe: prolonged or persistent crying, child could not be comforted and refused to play.
**p<0.01 when compared with DTP.
†† Diphtheria and tetanus toxoids and whole cell pertussis vaccines manufactured by Lederle Laboratories.
Hib capsular polysaccharide antibody (anti-PRP) levels indicative of clinical protection
(≥1 µg/mL). Testing of sera from a group of 12 infants administered hepatitis B vaccine
simultaneously with the other two vaccines at ages 2 and 4 months documented a
protective antibody response in 11 of the infants (93%) (i.e., anti-hepatitis B surface
antigen [anti-HBs] levels of >10 mIU/mL). Testing of sera from another subset of 20
infants who were administered OPV simultaneously with the other vaccines at ages 2,
4, and 6 months demonstrated that 100% had protective neutralizing antibody to all
three poliovirus types. Children (n=9) to whom Tripedia®, ActHIB®, and measles,
mumps, and rubella (MMR) vaccine were administered simultaneously at separate
sites developed antibody to measles, mumps, and rubella. Simultaneous administra-
tion of Tripedia® and inactivated poliovirus vaccine (IPV) or varicella vaccine has not
On September 27, 1996, FDA licensed TriHIBit™ (ActHIB® vaccine reconstituted
with Tripedia® vaccine) for the fourth doses of the diptheria, tetanus, and pertusssis
vaccine series and the Hib vaccine series. When ActHIB® is combined with Tripedia®
by reconstitution, each dose contains 10 µg of purified Hib capsular polysaccharide
conjugated to 24 µg of inactivated tetanus toxoid and 8.5% of sucrose, in addition to
the content of Tripedia®.
In a randomized clinical trial, children aged 15–20 months were administered either
Tripedia® and ActHIB® vaccines at separate sites (n=98) or combined as a single dose
(n=93) (Connaught Laboratories, Inc., Tripedia® package insert). Before the study be-
gan, these children all had received three doses of a Hib conjugate vaccine and three
doses of whole-cell DTP at approximately ages 2, 4, and 6 months. One month after
administration of the fourth dose, 100% of the children in both groups had anti-PRP
antibody concentrations ≥1 µg/mL, an indication of long-term protection against inva-
sive H. influenzae type b disease. The proportions of children with protective antibody
responses to diphtheria and tetanus toxoids were also high and similar in the two
groups. The proportions of children who had fourfold or greater serum antibody
responses to PT (measured by enzyme-linked immunosorbent assay [ELISA] or Chi-
nese hamster ovary [CHO] cell assay) were >85% in both groups. Among children who
received TriHIBit™ , the proportion with fourfold or greater antibody responses to FHA
was slightly lower. The clinical importance of this difference is not known.
TriHIBit™ has been licensed for use as the fourth dose of the two vaccination series
on the basis of immunogenicity and safety data. Its protective efficacy when used for
this purpose has not been evaluated.
10 MMWR March 28, 1997
The safety of TriHIBit™ was evaluated in two studies involving a total of 960 chil-
dren who had each received three doses of a Hib vaccine and three doses of
whole-cell DTP vaccine at approximately ages 2, 4, and 6 months (Connaught Labora-
tories, Inc., Tripedia® package insert). At age 15–20 months, these children were
administered the fourth dose of Tripedia® and ActHIB® vaccines either combined by
reconstitution as a single injection or as two injections at separate sites. Rates of local
and systemic reactions were similar in the two groups. Local reactions were mild and
resolved within 48 hours following vaccination. The most common local reaction was
pain at the injection site.
When TriHIBit™ was administered to children aged 15–20 months (n=47) simulta-
neously with MMR vaccine, >95% developed serum antibody to measles, mumps, and
rubella at levels indicative of protection against these diseases (Connaught Laborato-
ries, Inc., Tripedia® package insert). Immune responses to OPV or IPV and hepatitis B
vaccine when administered simultaneously with TriHIBit™ have not been studied.
On December 30, 1996, FDA licensed ACEL-IMUNE® for all five doses of the recom-
mended diphtheria, tetanus, and pertussis vaccination series among children aged 6
weeks–6 years. Each dose of the acellular pertussis component of ACEL-IMUNE® con-
tains approximately 34.4 µg of FHA, 3.2 µg of inactivated PT, 1.6 µg of Pn, and 0.8 µg of
Fim type 2. The acellular pertussis vaccine components are purified by ammonium
sulfate fractionation and sucrose density gradient centrifugation. PT is detoxified by
treatment with formaldehyde. Each dose of ACEL-IMUNE® contains 9.0 Lf units of
diphtheria toxoid, 5.0 Lf units of tetanus toxoid, and 300 hemagglutinating units of
acellular pertussis vaccine. The FHA and PT components both exhibit hemagglutinat-
ing activity. The combined components are adsorbed to aluminum hydroxide and
aluminum phosphate and preserved with 1:10,000 thimerosal (Table 1).
Data from the Multicenter Acellular Pertussis Trial provide evidence of the immuno-
genicity of ACEL-IMUNE® (26). Investigators measured levels of serum antibody to
each of the four vaccine antigens after administration of three doses. The percentages
of vaccinees with fourfold or greater increases in antibody titer (compared with pre-
vaccination levels) were: PT, 67%; FHA, 80%; Pn, 71%; and Fim, 59%. The percentages
of these children who developed diphtheria antibody levels of ≥0.1 u/mL and tetanus
antibody levels of ≥0.01 u/mL (i.e., indications of immunity against these diseases)
were 86% and 100%, respectively. Antibody responses observed among children in
the United States were similar to those observed among children in the study in Ger-
many that demonstrated the efficacy of ACEL-IMUNE®.
Antibody response to ACEL-IMUNE® when administered to children aged 12–
14 months was evaluated in a clinical trial (Wyeth-Lederle Vaccines and Pediatrics,
Vol. 46 / No. RR-7 MMWR 11
unpublished data). ACEL-IMUNE® was administered as a fourth dose to children aged
12–14 months (n=58) or 15–18 months (n=50) who had previously received three
doses of whole-cell DTP. In both age groups, >85% of the children had twofold or
greater antibody responses to PT, FHA, Pn, and Fim.
Efficacy of ACEL-IMUNE® was assessed in a prospective study in Erlangen, Ger-
many (Wyeth-Lederle Vaccines and Pediatrics, ACEL-IMUNE® package insert). Infants
were randomly assigned to groups that were administered either ACEL-IMUNE® or
whole-cell DTP (distributed by Wyeth-Lederle Vaccines and Pediatrics) at a mean age
of 3, 5, 7, and 17 months. A third group of infants (not selected randomly) received DT
at ages 3, 5, and 17 months. In this study, pertussis was defined as cough illness last-
ing ≥21 days with at least one pertussis-associated symptom (paroxysms, whoop, or
post-tussive vomiting) confirmed by culture, serology, or epidemiologic link to a cul-
ture-positive household contact. Between the third and fourth doses, the efficacy of
ACEL-IMUNE® (compared with DT) was 73% (95% CI=51%–86%) and the efficacy
of whole-cell DTP 83% (95% CI=65%–92%). After four doses, the efficacy of ACEL-
IMUNE® was 85% (95% CI=76%–90%), and that of whole-cell DTP was 94% (95%
CI=89%–97%). Considering the full observation period after the third and fourth doses,
the adjusted efficacy of ACEL-IMUNE® was 81% (95% CI=73%–87%) compared with
91% (95% CI=85%–95%) for whole-cell DTP.
Studies from the United States and Germany provide data concerning the fre-
quency and nature of adverse events that occur after administration of ACEL-IMUNE®.
In the Multicenter Acellular Pertussis Trial, children who were administered ACEL-
IMUNE® experienced fewer local adverse events (e.g., pain, redness, or swelling at the
injection site) and systemic adverse events (e.g., temperature >101 F [>38.3 C], or
fussiness) after any of the first three doses than children who were administered
whole-cell DTP (Table 3) (29 ). Similarly, in other studies conducted in the United
States and Germany, adverse events (local and systemic) after any of the initial four
doses occurred less frequently among children who received ACEL-IMUNE® than
among children administered whole-cell DTP (Wyeth-Lederle Vaccines and Pediatrics,
ACEL-IMUNE® package insert). Rates of adverse events increased with the number of
previous doses of ACEL-IMUNE® administered, but were lower than rates for children
who received the same number of doses of whole-cell DTP. Among 357 children who
were administered five doses of ACEL-IMUNE®, adverse events occurred no more fre-
quently than among children in previous studies (historical controls) who received
five doses of whole-cell DTP (Wyeth-Lederle Vaccines and Pediatrics, ACEL-IMUNE®
In the efficacy trial in Germany (n=16,642 doses of ACEL-IMUNE®), the following
rates of moderate to severe adverse events (per 1,000 doses administered) were
observed within 72 hours after administration of the vaccine: persistent or unusual
cry, 1.14; temperature ≥105 F (≥40.5 C), 0.06; febrile seizures (no other type of seizure
occurred), 0.06; and hypotonic hyporesponsive episodes, 0 (Wyeth-Lederle Vaccines
12 MMWR March 28, 1997
and Pediatrics, ACEL-IMUNE® package insert). Rates of all these adverse events were
higher among children who received whole-cell DTP.
A clinical trial examined the frequency of local reactions (e.g., erythema, indura-
tion, or tenderness) and systemic reactions (e.g., fever, fussiness, drowsiness, or
anorexia) among children aged 12–14 months or 15–18 months, all of whom had pre-
viously received three doses of whole-cell DTP. Differences in the frequency of adverse
reactions in the two age groups were not statistically significant (Wyeth-Lederle Vac-
cines and Pediatrics, unpublished data).
Neither anaphylaxis nor encephalopathy occurred during clinical trials that in-
volved administration of 25,899 doses of ACEL-IMUNE®. Six deaths of infants or
young children who participated in these trials were reported to study investigators;
none was vaccine-related and all occurred >4 weeks after vaccination (Wyeth-Lederle
Vaccines and Pediatrics, ACEL-IMUNE® package insert). The reactogenicity of ACEL-
IMUNE® among persons aged ≥7 years has not been evaluated.
The immunogenicity of ACEL-IMUNE® when administered simultaneously with
other recommended childhood vaccines was evaluated in three studies. ACEL-
IMUNE®, Hib vaccine, and hepatitis B vaccine were administered simultaneously to
77 infants at ages 2, 4, and 6 months. After administration of the third dose, serum
samples from 94% of the infants demonstrated anti-PRP antibodies indicative of clini-
cal protection (≥1 µg/mL), and all of the infants evaluated (n=74) had antibody levels
indicative of protection against hepatitis B (i.e., anti-HBs titers of >10 mIU/mL) (Wyeth-
Lederle Vaccines and Pediatrics, ACEL-IMUNE® package insert). In another clinical
study, 30 infants were administered OPV simultaneously with ACEL-IMUNE® at ages
2 and 4 months; ≥90% had protective neutralizing antibody to all three poliovirus types
at age 6 months. When MMR vaccine was administered simultaneously with ACEL-
IMUNE® to children aged 15–18 months (n=48), ≥92% developed serum antibody titers
indicative of protection against measles, mumps, and rubella. Similar results were
obtained when whole-cell DTP was administered simultaneously with OPV or MMR
vaccine (31 ). Simultaneous administration of ACEL-IMUNE® and IPV or varicella vac-
cine has not been evaluated.
On January 29, 1997, FDA licensed Infanrix™ for use as the initial four doses of the
recommended diphtheria, tetanus, and pertussis vaccination series among children
aged 6 weeks–6 years. Infanrix™ is also licensed for all remaining doses in the sched-
ule for children who have received one or more doses of whole-cell DTP vaccine. Each
dose of Infanrix™ contains 25 µg PT, 25 µg FHA, 8 µg Pn, 25 Lf of diphtheria toxoid,
and 10 Lf of tetanus toxoid (Table 1). The three antigens in the acellular pertussis vac-
cine component are separately purified in successive chromatographic steps
(hydrophobic, affinity, ion exchange, and size exclusion processes). Formalin and glu-
taraldehyde are used to detoxify PT; FHA and Pn are treated with formalin. The
combined components are adsorbed onto ≤0.625 mg of aluminum (as aluminum
hydroxide) and preserved with 2-phenoxyethanol.
Vol. 46 / No. RR-7 MMWR 13
In the Multicenter Acellular Pertussis Trial, three doses of Infanrix™ were adminis-
tered to children at ages 2, 4, and 6 months. One month after the third dose,
investigators measured fourfold or greater antibody responses to PT, FHA, and Pn in
≥83% of children who received Infanrix™ , a higher proportion than observed among
recipients of whole-cell DTP (26 ). All the children who were administered Infanrix™
developed diphtheria antibody titers of ≥0.1 u/mL and tetanus antibody titers of
≥0.01 u/mL (i.e., indications of immunity against these diseases). Whether their
primary vaccination was with Infanrix™ or whole-cell DTP, >86% of children aged 15–
20 months had a fourfold or greater rise in serum antibody to each of the pertussis
antigens in the vaccine after administration of Infanrix™ as the fourth dose
(M. E. Pichichero, unpublished data). The immunogenicity of Infanrix™ administered
as a fourth dose to children aged 12–14 months has not been studied.
The efficacy of Infanrix™ was evaluated in two separate studies (Table 2). In Italy,
researchers compared the efficacy of Infanrix™ , DTaP manufactured by Chiron
Biocine, whole-cell DTP manufactured by Connaught Laboratories, and DT in a ran-
domized controlled trial that enrolled more than 15,000 children (15 ). Participants
received three doses of one of the vaccines at ages 2, 4, and 6 months. The efficacy of
Infanrix™ in preventing pertussis disease (defined as paroxysmal cough ≥21 days du-
ration, with culture or serologic confirmation of infection with B. pertussis) was 84%
(95% CI=76%–89%). The efficacy of whole-cell DTP was 36% (95% CI=14%–52%). After
the trial, children were followed in an observational study to an average age of
33 months (range: 20–39 months); the efficacy of Infanrix™ remained high through-
out this followup period (78%, 95% CI=62%–87%) (SmithKline Beecham Pharma-
ceuticals, Infanrix™ package insert).
The second study, conducted in six areas in Germany, was a household contact
study. In preparation for this study, three doses of Infanrix™ were administered at
ages 3, 4, and 5 months to more than 22,000 infants as part of a large immunogenicity
and safety study (23 ). Infants who did not participate in this study could have received
whole-cell DTP vaccine (manufactured by Behringwerke, A.G.) or DT vaccine. The effi-
cacy study included 453 households with confirmed cases of pertussis in which 360
contact children aged 6–47 months were eligible for inclusion in the vaccine efficacy
calculations. A case of pertussis was defined as ≥21 days of paroxysmal cough illness
plus confirmation of B. pertussis infection by culture and/or serologic testing. The ef-
ficacy of Infanrix™ was 89% (95% CI=77%–95%); the efficacy of whole-cell DTP was
98% (95% CI=83%–100%).
The occurrence of adverse events following vaccination with Infanrix™ was evalu-
ated in clinical studies involving approximately 30,000 children. In these studies,
28,749 infants received Infanrix™ as a three dose primary series, 5,830 children
received Infanrix™ as a fourth dose following three doses of Infanrix™ , and 22 chil-
dren received Infanrix™ as a fifth dose following four doses of Infanrix™ . In addition,
14 MMWR March 28, 1997
439 children and 169 children received Infanrix™ as a fourth or fifth dose following
three or four doses of whole-cell DTP vaccine, respectively. In comparative studies,
administration of Infanrix™ was followed by fewer of the local and systemic adverse
reactions commonly associated with whole-cell DTP vaccination (15,29,32–34 ). How-
ever, results of these studies demonstrated that the rates of erythema, swelling, and
fever increased with each successive dose of Infanrix™ (SmithKline Beecham Phar-
maceuticals, Infanrix™ package insert). In the Multicenter Acellular Pertussis Trial,
local and common systemic adverse events occurred less frequently following any
dose of Infanrix™ in the primary series than following any dose of whole-cell DTP
(Table 3) (29 ).
The efficacy study conducted in Italy monitored the frequency of moderate to
severe adverse events occurring after administration of any of the primary doses
of Infanrix™ . Rates (per 1,000 doses administered) of adverse events occurring
≤48 hours after administration were: persistent crying ≥3 hours duration, 0.44; sei-
zures, 0.07; and temperature ≥104 F(≥40.0 C), 0.36. These rates were similar to or
slightly higher than the rates reported among children who were administered DT, but
lower than those for children who received whole-cell DTP. In this trial, no hypotonic
hyporesponsive episodes occurred among children to whom Infanrix™ was adminis-
In the safety study in Germany, data were available regarding 1,809 children who
received three doses of Infanrix™ at ages 3, 4, and 5 months and a fourth dose at a
mean age of 20 months. The percentages of children who experienced each of the
adverse events ≤3 days after administration of the fourth dose were: redness, 46%;
swelling, 35%; pain, 26%; fever ≥100.4 F (≥38 C), 26%; and restlessness, 16%. In this
study the rates of redness, swelling, pain, and fever increased with successive doses
of Infanrix™ (SmithKline Beecham Pharmaceuticals, Inc., Infanrix™ package insert).
Additional safety data are available from another study conducted in Germany
(SmithKline Beecham Pharmaceuticals, Inc., Infanrix™ package insert). Children aged
13–27 months received Infanrix™ or whole-cell DTP (manufactured by Behringwerke,
A.G.) as a fourth dose. These children had previously received three doses of the same
vaccine. Among children administered Infanrix™ as the fourth dose, the incidence of
redness, swelling, pain, fever, and restlessness was lower than among children
administered whole-cell DTP as the fourth dose.
Infanrix™ has not been licensed previously for administration of the fourth or fifth
dose to children who have received three or four doses of whole-cell DTP. Two studies
conducted in the United States examined the frequency of adverse events among chil-
dren who had previously received three or four doses of whole-cell DTP vaccine at
approximately ages 2, 4, 6, and 15–18 months (Table 4). Children aged 15–20 months
received Infanrix™ or whole-cell DTP vaccine as the fourth dose; children aged 4–
6 years were administered Infanrix™ or whole-cell DTP as the fifth dose (33,34 ).
Significantly fewer local and systemic adverse events were reported following ad-
ministration of Infanrix™ than following whole-cell DTP vaccine.
In the safety study in Germany, edematous swelling of the entire thigh into which
the vaccine was injected was reported spontaneously by parents or care-givers of 62
of 5,361 vaccinees (1.2%) after administration of the fourth dose. The swelling gener-
ally began within 48 hours of vaccination and resolved spontaneously without
sequelae during an average of 4 days. In other countries where Infanrix™ has been
Vol. 46 / No. RR-7 MMWR 15
licensed, this type swelling has been reported rarely following administration of Infan-
rix™ for any dose, including the primary series (SmithKline Beecham
Pharmaceuticals, Infanrix™ package insert). Edematous swelling has also been re-
ported following administration of other DTaP vaccines, acellular pertussis vaccine
alone (without DT), whole-cell DTP vaccine and other vaccines (19,35–37 ). However,
the precise frequency of these reactions among vaccinated children is unknown.
Data are insufficient to evaluate the safety of administration of a fifth dose of Infan-
rix™ to children aged 4–6 years who have received Infanrix™ for the previous four
doses. Additional information regarding the immunogenicity and safety of a fifth dose
of Infanrix™ administered to children who have received four prior doses of the same
vaccine is being collected. This information is expected to be available before infants
who receive Infanrix™ for the first four doses require a fifth dose at age 4–6 years. The
safety of Infanrix™ when administered to persons aged ≥7 years has not been
In a clinical trial in the United States, Infanrix™ was administered simultaneously,
at separate sites, with hepatitis B vaccine, Hib vaccine, and OPV to children aged 2, 4,
and 6 months. One month after the third dose, 100% of infants (n=64) administered
hepatitis B vaccine simultaneously with Infanrix™ demonstrated anti-HBs antibodies
TABLE 4. Adverse events (%) occurring <3 days after administration of Infanrix™ to
children aged 15–20 months and 4–6 years*†
15–20 months 4–6 years
vaccine (N= 57)
Redness 23§ 45§ 19§ 40§
Swelling 14 24 15§ 33§
Pain¶ 5§ 38§ 12§ 40§
Fever >100.5 F** 2§ 20§ 1§ 12§
Fussiness 34§ 69§ 20 30
Drowsiness 9§ 24§ 11 18
Poor appetite 9§ 20§ 6§ 16§
Vomiting 2 0 1 4
*All children had previously been administered diphtheria and tetanus toxoids and whole-cell
pertussis (DTP) vaccine: children aged 15–20 months had received three doses; children
aged 4–6 years had received four doses.
†Sources: Bernstein HH, Rothstein EP, Reisinger KS, et al. Comparison of a three component
acellular pertussis vaccine with a whole-cell pertussis vaccine in 15- through 20-month-old
infants. Pediatrics 1994;93:656–9 and Annunziato PW, Rothstein EP, Bernstein HH, Blatter
MM, Reisinger KS, Pichichero ME. Comparison of a three component acellular pertussis
vaccine with a whole-cell pertussis vaccine in 4- through 6-year-old children. Arch Pediatr
Adolesc Med 1994;148:503–7.
¶Moderate or severe=cried or protested to touch or cried when arm moved.
16 MMWR March 28, 1997
≥10 mIU/mL and 90% of infants (n=72) who received Hib vaccine simultaneously with
Infanrix™ achieved anti-PRP antibodies ≥1 µg/mL (i.e., antibody levels indicative of
protection against these diseases). The percentage of infants who were administered
OPV simultaneously with Infanrix™ (n=60–61) who developed protective neutralizing
antibody to poliovirus types 1, 2, and 3 ranged from 96% to 100% (38 ). No data are
available regarding antibody responses to MMR vaccine, varicella vaccine, or IPV
when administered simultaneously with Infanrix™ .
Recommended Childhood Vaccination Schedule
The routine diphtheria, tetanus, and pertussis vaccination schedule for children
aged <7 years comprises five doses of vaccine containing diphtheria, tetanus, and
pertussis antigens (Table 5). Three (primary) doses should be administered during the
first year of life, generally at ages 2, 4, and 6 months. To maintain adequate immunity
during preschool years, the fourth (first booster) dose is recommended for children
TABLE 5. Routine diphtheria, tetanus, and pertussis vaccination schedule for children
aged <7 years—United States, 1997
Primary 1 2 months Age ≥6 weeks DTaP
Primary 2 4 months 4–8 weeks after first dose¶ DTaP
Primary 3 6 months 4–8 weeks after second dose¶ DTaP
First Booster 15–18 months** 6–12 months after third dose¶ DTaP††
Second Booster Age 4–6 years, before
entering kindergarten or
elementary school (not
necessary if fourth dose [first
booster] is administered after
Every 10 years after last dose Td§§
*Diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP); diphtheria and tetanus
toxoids and whole-cell pertussis vaccine (DTP) is an acceptable alternative to DTaP for any
of the five doses.
†Use diphtheria and tetanus toxoids, adsorbed (DT) if encephalopathy has occurred after
administration of a previous dose of pertussis-containing vaccine. If the child is age ≥1 year
at the time the first dose of DT is administered, a third dose administered 6–12 months
after the second dose completes primary vaccination with DT.
§Whenever possible, the same DTaP product should be used for all doses. If the same product
is not available, Tripedia®, ACEL-IMUNE®, and Infanrix™ can be used interchangeably.
¶Prolonging the interval does not require restarting the series.
**If the interval between the third and fourth doses is ≥6 months and the child is not likely
to return for a visit at the recommended age, the fourth dose of either DTaP or DTP may
be administered as early as age 12 months.
††TriHIBit™ can be administered as the fourth dose following a primary series with either
DTaP or whole-cell DTP and a primary series with any Haemophilus influenzae type b
§§Tetanus-diphtheria toxoids absorbed (Td) (for adult use).
Vol. 46 / No. RR-7 MMWR 17
aged 15–18 months. The fourth dose should be administered ≥6 months after the
third. If the interval between the third and fourth doses is ≥6 months and the child is
not likely to return for a visit at the recommended age, the fourth dose of either DTaP
or whole-cell DTP may be administered as early as age 12 months. The fifth (second
booster) dose is recommended for children aged 4–6 years to confer continued pro-
tection against disease during the early years of schooling. A fifth dose is not
necessary if the fourth dose in the series is administered on or after the fourth birth-
DTaP vaccines are efficacious when administered to infants as the primary series
(i.e., doses 1–3). In addition, local reactions, fever, and other systemic events occur
substantially less often after DTaP administration than after administration of whole-
cell DTP. Therefore, DTaP vaccines are recommended for all five doses in the
vaccination schedule. For children who have started the vaccination series with one,
two, three, or four doses of whole-cell DTP, DTaP is also recommended for all remain-
ing doses in the schedule. During the period of transition from use of whole-cell DTP
to DTaP, whole-cell DTP is an acceptable alternative to DTaP for any of the five doses.
For the first four doses, whole-cell DTP combined with Hib vaccine (DTP-Hib vaccine)
is an acceptable alternative to DTaP and Hib vaccine administered at separate sites.
Three acellular pertussis vaccines (Tripedia® and Infanrix™ for the first four doses
and ACEL-IMUNE® for all five doses) are licensed for the diphtheria, tetanus, and per-
tussis vaccination series. FDA has not approved Tripedia® or Infanrix™ as the fifth
dose among persons who have received only Tripedia® or only Infanrix™ for the first
four doses in the vaccination series, because data are insufficient to evaluate their
safety in this situation. However, such data should be available before infants vacci-
nated with four doses of these vaccines require a fifth dose at age 4–6 years.
TriHIBit™ (ActHIB® reconstituted with Tripedia®) is licensed only for the fourth
dose of the vaccination series, and is not licensed for the first three doses. TriHIBit™
can be used for the fourth dose following three doses of either DTaP or whole-cell DTP
and a primary series of any Hib vaccine.
Dosage and Administration
The dose of all four vaccines—Tripedia®, TriHIBit™ , ACEL-IMUNE®, and
Infanrix™ —is 0.5 mL, administered intramuscularly. Fractional doses (<0.5 mL)
should not be administered. The preferred injection sites are the anterolateral aspect
of the thigh and the deltoid muscle of the upper arm (39 ).
To administer TriHIBit™ (ActHIB® reconstituted with Tripedia®) (Connaught Labora-
tories, Inc., ActHIB® package insert):
• Cleanse the rubber stoppers of both vials with a suitable germicide.
• Thoroughly agitate the vial of Tripedia®
. Insert the needle of a syringe through
the vial’s rubber stopper and withdraw 0.6 mL of Tripedia®
18 MMWR March 28, 1997
• Inject Tripedia®
into the vial of lyophilized ActHIB®
. Agitate vial thoroughly; the
combined reconstituted vaccines should appear whitish in color.
• Withdraw 0.5 mL dose of the combined vaccines; administer intramuscularly
within 30 minutes of reconstitution.
Interchangeable Use of Acellular Pertussis Vaccines
Whenever feasible, the same brand of DTaP vaccine should be used for all doses of
the vaccination series. Data do not exist regarding the safety, immunogenicity, and
efficacy of using DTaP vaccines from different manufacturers for successive doses of
the primary or booster vaccination series. However, the vaccine provider may not
know or may not have available the type of DTaP vaccine previously administered to a
child. Neither circumstance should present a barrier to administration of the vaccine
and any of the licensed DTaP vaccines may be used to complete the vaccination series.
Simultaneous Administration of Vaccines
Limited data regarding simultaneous administration of the first three doses of DTaP
with other childhood vaccines indicate no interference with response to any of these
other antigens. Data are available regarding administration of DTaP with the other
vaccines recommended at the same time as the fourth and fifth doses of the diphthe-
ria, tetanus, and pertussis series (i.e., Hib vaccine, OPV, MMR vaccine, and varicella
vaccine), and regarding administration of whole-cell DTP (all doses in the series) with
these vaccines (40 ). On the basis of this experience, DTaP may be administered simul-
taneously with hepatitis B vaccine, Hib vaccine, and IPV or OPV to infants at ages 2, 4,
or 6 months as indicated in the recommended childhood vaccination schedule (41 ).
All vaccines appropriate to the age and previous vaccination status of the child should
be administered simultaneously including DTaP, Hib vaccine, IPV or OPV, hepatitis B
vaccine, MMR vaccine, and varicella vaccine.
Vaccination of Infants and Young Children Who Have a Personal or Family
History of Seizures
Infants and young children who have had previous seizures (whether febrile or
nonfebrile) are at greater risk for seizures after administration of whole-cell pertussis
vaccination than are infants who do not have such a history (42 ). Because these reac-
tions may be caused by the fever induced by whole-cell DTP and because DTaP is less
frequently associated with moderate to high fever, DTaP is the vaccine of choice when
pertussis vaccination is considered for these children.
Among infants and children with a history of previous seizures, it is prudent to
delay pertussis vaccination until the child’s neurologic status has been assessed.
Infants and children with a stable neurologic condition, including well-controlled sei-
zures, may be vaccinated with DTaP. Infants with evolving neurologic conditions
should not be vaccinated until a treatment regimen has been established and the con-
dition has stabilized. Acetaminophen or ibuprofen may be administered to these
Vol. 46 / No. RR-7 MMWR 19
children at the time of DTaP vaccination and every 4 hours for 24 hours thereafter to
reduce the possibility of postvaccination fever.
Data from one study indicate that infants and young children who have a parent or
sibling with a history of convulsions are more likely to have seizures following whole-
cell DTP vaccination than those without such histories (43 ). However, seizures occur
infrequently after administration of whole-cell DTP, are usually febrile in nature, and
generally have a benign outcome (44 ). An estimated 5%–7% of children have parents
or siblings with a history of convulsions (43 ). If these children were exempted from
pertussis vaccination, unvaccinated persons and the general population might face an
increased risk for pertussis. Therefore, a family history of convulsions or other central
nervous system disorders is not a contraindication to pertussis vaccination. Acetami-
nophen or ibuprofen may be administered to these children at the time of DTaP
vaccination and every 4 hours for 24 hours thereafter to reduce the possibility of
Children Who Have Had Pertussis Disease
Although pertussis disease is likely to confer immunity against pertussis, the dura-
tion of such immunity is unknown. Children with well-documented pertussis disease
(i.e., positive culture for B. pertussis or epidemiologic linkage to a culture-positive
case) should be administered DT vaccine for the remaining doses of the vaccination
series to ensure that they are protected against diphtheria and tetanus. Some experts
recommend including the pertussis component for subsequent vaccination of infants
who have had culture-proven pertussis because infants may have a suboptimal im-
mune response following B. pertussis infection (45 ).
Pertussis Vaccination for Persons Aged ≥7 Years
Pertussis vaccines are presently licensed for use only among children aged
6 weeks–6 years. In the United States, adolescents and adults whose immunity has
waned are an important reservoir for B. pertussis and may infect unvaccinated young
children. In the future, booster doses of adult formulations of acellular pertussis vac-
cines may be recommended to prevent the occurrence and spread of the disease
among these older persons. However, acellular pertussis vaccines combined with
diphtheria and tetanus toxoids will need to be reformulated for use in adults because
all infant formulations contain more diphtheria toxoid than is recommended for per-
sons aged ≥7 years. Recommendations regarding routine vaccination of adults will
require additional research (e.g., studies of the incidence, severity, and cost of pertus-
sis among adolescents and adults; studies of the effectiveness and safety of adult
formulations of DTaP; and studies of the cost-effectiveness of a strategy of adult
Mild systemic reactions such as fever, drowsiness, fretfulness, and anorexia may
occur after both whole-cell DTP vaccination and DTaP vaccination. However, data con-
cerning adverse reactions following the first four doses indicate that mild reactions
are less common among children who receive DTaP. These reactions are self-limited
and can be managed safely with symptomatic treatment.*
*For a complete discussion, see the general ACIP statement on diphtheria, tetanus, and pertussis
and the supplementary statements on DTaP (16,17,42 ).
20 MMWR March 28, 1997
Moderate-to-severe systemic events (e.g., temperature of ≥105 F [≥40.5 C]; febrile
seizures; persistent, crying lasting ≥3 hours; and hypotonic hyporesponsive episodes)
have been reported rarely after administration of DTaP, and occur less frequently
among children administered DTaP than among children administered whole-cell DTP.
Data from the Vaccine Adverse Event Reporting System (VAERS)* were used to
compare rates of fever, seizures, and hospitalizations among children who, having
had ≥3 previous doses of whole-cell DTP, were administered either DTaP or whole-cell
DTP vaccines for the fourth or fifth doses (46 ). During 1991–1993, approximately
5 million doses of DTaP (distributed by Connaught Laboratories, Inc., or Wyeth-Led-
erle Vaccines and Pediatrics) and 27 million doses of whole-cell DTP were distributed
for use among children aged 15 months–6 years. Adverse events were reported
significantly less commonly among the children who received DTaP. VAERS is a pas-
sive surveillance system and these data should be interpreted with caution because
the events reported may be linked to vaccine administration only by temporal
If either of the following events occurs after administration of DTaP or whole-cell
DTP, subsequent vaccination with DTaP or whole-cell DTP is contraindicated:
• An immediate anaphylactic reaction. Further vaccination with any of the three
components of DTaP or whole-cell DTP should be deferred because of uncer-
tainty as to which component of the vaccine might be responsible. Because of
the importance of tetanus vaccination, persons who experience anaphylactic re-
actions may be referred to an allergist for evaluation and (if specific allergy can
be demonstrated) desensitized to tetanus toxoid.
• Encephalopathy not attributable to another identifiable cause (e.g., an acute, se-
vere central nervous system disorder occurring within 7 days after vaccination
and generally consisting of major alterations in consciousness, unresponsive-
ness, or generalized or focal seizures that persist more than a few hours, without
recovery within 24 hours.) In such cases, DT vaccine should be administered for
the remaining doses in the vaccination schedule to ensure protection against
diphtheria and tetanus.
If any of the following events occurs within the specified period after administra-
tion of either whole-cell DTP or DTaP, vaccine providers and parents should evaluate
the risks and benefits of administering subsequent doses of a pertussis-containing
• Temperature of ≥105 F (≥40.5 C) within 48 hours, not attributable to another iden-
• Collapse or shock-like state (hypotonic hyporesponsive episode) within 48 hours.
*VAERS is a passive surveillance system for reporting of adverse events temporally associated
with administration of vaccines.
Vol. 46 / No. RR-7 MMWR 21
• Persistent crying lasting ≥3 hours, occurring within 48 hours.
• Convulsions with or without fever, occurring within 3 days.
In circumstances in which the benefits of further pertussis vaccination outweigh the
possible risks (e.g., during an outbreak of pertussis), DTaP should be administered for
the subsequent doses.
REPORTING OF ADVERSE EVENTS AFTER VACCINATION
As with any newly licensed vaccine, surveillance for rare adverse events potentially
associated with administration of DTaP is important for assessing its safety in large-
scale use. The National Childhood Vaccine Injury Act of 1986 requires health-care
providers to report serious adverse events that follow pertussis vaccination (47 ). The
events that must be reported are detailed in the Reportable Events Table within this
Act, and include anaphylaxis or anaphylactic shock, encephalopathy (or encephalitis),
shock collapse or hypotonic hyporesponsive collapse, and any acute complication or
sequela (including death) of these events. Adverse reactions should be reported to
VAERS (48 ). VAERS reporting forms and information are available 24 hours a day by
calling (800) 822-7967.
VACCINE INJURY COMPENSATION
The National Vaccine Injury Compensation Program, established by the National
Childhood Vaccine Injury Act of 1986, provides a mechanism through which compen-
sation can be paid on behalf of a person thought to have been injured or to have died
as a result of receiving a vaccine covered by the program (49,50 ).
A Vaccine Injury Compensation Table in the Act lists the vaccines covered by the
program and the injuries, disabilities, and conditions (including death) for which com-
pensation may be paid. Development or onset of anaphylaxis or anaphylactic shock
≤4 hours or encephalopathy with onset ≤72 hours after administration of pertussis
vaccine (or sequelae of these conditions) are potentially compensable under this law.
Persons may be compensated for an injury listed in the established table or one that
can be demonstrated to result from administration of a listed vaccine. Additional infor-
mation about the program is available.*
*National Vaccine Injury Compensation Program
Health Resources and Services Administration
Parklawn Building, Room 8-05
5600 Fishers Lane
Rockville, MD 20857
Telephone: (800) 338-2382 (24-hour recording)
Persons wishing to file a claim for vaccine injury should call or write to:
U.S. Court of Federal Claims
717 Madison Place, NW
Washington, DC 20005
Telephone: (202) 219-9657
22 MMWR March 28, 1997
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Vol. 46 / No. RR-7 MMWR 25
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